The drug seizure was announced by Pol Maj Gen Thesa Siriwathok, acting Nakhon Si Thammarat police chief, at a press conference on Sunday morning.
Pol Maj Gen Thesa said the checkpoint was set up on Asian Highway 41 at Ban Samnakkhan in tambon Sam Tambon on information that a large quantity of drugs would be delivered from the North to the South along this route.
At 9.30am on Saturday, police at the checkpoint stopped a car for a search. They found a total of 298,000 methamphetamine pills hidden in all four doors of the car and two radio speakers.
Abdulloh Dura-o, 34, the driver, and Nayo Suedi, 40, both of Narathiwat's Rangae district, were arrested.
The two said the drugs had been earlier delivered from the North to a storage area in Bangkok. They were hired for 200,000 baht each to deliver the drugs from Bangkom to Narathiwat.